Roy van Rijn writes: A couple of weeks ago, in a spare weekend, I wrote software that could recognise music through listening to the microphone, much like SoundHound and Shazam. After populair demand I was just about to release the code into the open source community when I got an email from Landmark Digital Services LLC. They claim my hobby project is infringing their patents. This took me on a journey to find out more about software patents and the validity of the requests I got from the company.